The applicant's long term goal is to develop effective strategies to prevent or attenuate the damage of biliary cirrhosis from chronic biliary obstruction based on an understanding of the genes and cellular mechanisms regulating the bile duct epithelia (BDE) function and response to biliary injury. The departments of Molecular Genetics and Surgery at the University of Illinois at Chicago are fully committed to support this endeavor by providing the candidate with protected time, core facilities usage, laboratory space and continuing research educational opportunities. The mentor is a major contributor to the field of tissue specific gene regulation and has identified several hepatocyte transcription factors essential for liver gene expression and function, including hepatocyte nuclear factor HNF-6 which is important to the performance of this project. The goal of this project is to understand the transcriptional mechanisms regulating BDE gene expression and function during the BDE proliferative response to biliary obstruction, and the role of the early BDE proliferation in the pathogenesis of liver fibrosis using the animal model of common bile duct division. HNF-6 regulates important liver specific gene expression for hepatocyte function. Since HNF-6 is abundant in the BDE and its expression is diminished in the proliferating BDE following bile duct ligation, HNF-6 may regulate the expression of differentiated genes essential to BDE function. We will overexpress HNF-6 or inhibit HNF-6 function in BDE cell lines with an adenovirus expressing a dominant negative HNF-6 protein and use differential hybridization of gene array blots of mock infected or transduced cells to identify differentiated BDE genes. We will use an adenovirus HNF-6 expression vector to transduce the BDE and restore in vivo BDE expression of HNF-6 with the aim to inhibit BDE proliferation during mouse bile duct ligation. This in vivo intervention is anticipated to impede BDE dedifferentiation and proliferation. Bile duct specific target gene mRNA and protein expression will be assessed and the effect on the development of biliary fibrosis will be determined.